Of course the something from nothing is meant in the way of total energy.
I have no personal terminally confident opinion on this but it is absolutely possible that you have negative energy and positive energy adding up to zero in some extreme systems.
Two stars in a binary or a solar system in total are examples of systems with total energy that is negative because the sum of kinetic and potential is negative for bound systems. It does however have also mc^2 energy, self binding energy, that is way higher than this gravitational negative part.
To give you an idea;
A system of 2 masses that orbit each other at constant distance D have both 2mc^2 total rest mass energy. In order for the 2 m to orbit say in a perfect circle around their common center of mass (imagine them in a circle in a diameter in opposite ends with center of mass the center of the circle) you need to have ;
centripetal acceleration times mass = gravitational attraction
so mv^2/(D/2)=m*m*G/D^2 or 1/2*mv^2=1/2*1/2*m^2*G/D
Their potential energy is -Gm^2/D and from the above their kinetic energies are;
2*1/2*m*v^2=1/2*m^2*G/D
So total energy potential plus kinetic is -Gm^2/2D < 0
Add to that the gravitational binding energy of each mass and you have
(
https://en.wikipedia.org/wiki/Gravit...binding_energy )
-3.5*Gm^2/R each (radius R each)
for a total of -6/5*Gm^2/R-Gm^2/2D
Add to that Einstein rest mass energy of 2mc^2
And you have total energy roughly (not particularly wrong unless they orbit at relativistic speeds and even then its not that bad really until you reach levels that its already absurd to talk about stability as spherical systems) ;
2mc^2-6/5*Gm^2/R-Gm^2/2D
I offered the 2 masses for illustration of an example of a binary system that has clearly negative total energy.
If however one notices above the negative terms are dominated by the gravitational binding energy of each object one is left asking whether something like
mc^2-3/5*G*m^2/R can be near zero for some configuration.
That would require R=3/5GM/c^2 that is smaller than the Schwarzschild radius of a black hole of that mass m, rs=2GM/c^2
So you cannot have such a bound system that has net zero energy like this. It has already collapsed (plus better calculations needed then).
If you add other forms of energy though this may become possible in some cases. We need to explore these in detail but its premature to do so before the reframing of physics that is starting that is currently unavoidable.
I accuse Krauss and others moreover their intelligence and education for endless self promotion with all kinds of bs speculative theories that are not ever proven properly in their arguments but have some air of confidence that is audacious to reach book levels for wide audiences and endless lectures.
When reading such things just stay skeptic as much as you can unless the person actually takes it upon themselves to show you in detail what they are talking about and even the vulnerability of their own arguments.
You will have to imagine but not confidently claim so that indeed it may be possible that this universe is a quantum fluctuation of a greater system in which from our perspective it appears it lasts a great lifetime and from the other system it's just a fluctuation.
After all 10^-22 sec is a significant time for strong interactions (takes 3*10^-24 sec to travel the size of one proton with the speed of light) allowing an eternity of processes to exist in 1 sec whereas from out perspective the universe is only ~150 mil times older than the avg human lifetime (much less impressive eternity lol) or our lifetime 3 bil times that of a second.
So maybe under the right perspective we could be an "eternity" (as in long time frame) inside some short lived fluctuation if seen from another vantage point that makes it probable to emerge out of nothing.
It doesnt really emerge out of nothing though philosophically. It emerges out of the character of natural law or its self consistency that allows the process. You can only see it as nothing if the total energy is zero and as a zero total energy fluctuation if it doesnt persist for long in the greater system.
See also
https://en.wikipedia.org/wiki/Virtual_particle
Last edited by masque de Z; 02-01-2018 at 08:16 PM.